


Fire and Heat

by Lavender_chan



Series: Valentine's Day 2018 [3]
Category: Undertale (Video Game)
Genre: F/M, Monster Heat, Reader Is Not Chara, Reader Is Not Frisk, Smut, i might add this as a chapter for that fic later, this is set in the same universe as tale of fire and light
Language: English
Status: Completed
Published: 2018-02-14
Updated: 2018-02-14
Packaged: 2019-03-18 10:43:00
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 1,544
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13680075
Author URL: https://archiveofourown.org/users/Lavender_chan/pseuds/Lavender_chan
Summary: It’s Grillby’s first time going into his heat since he’s met you and really needs some relief.





	Fire and Heat

**Author's Note:**

  * For [FitofPaige](https://archiveofourown.org/users/FitofPaige/gifts).



> Happy Valentine's Day, Paigey~

“I’m back! Undyne and Alphys say hello!”

You shrugged your jacket off and hung it on the hooks by the door before you started to make your way down into the basement apartment that you shared with your boyfriend, Grillby. Above said apartment was the bar he owned that the two of you worked in, but you noticed that despite it being 2 in the afternoon, Grillby hadn’t turned on any lights in the kitchen. Maybe he was running late. Or maybe he was opening late because of the snow?

You called out again when you entered the modest living room/kitchen that welcomed you in from the cold, “Grillby? I’m back, love!”

The backpack you had been using as your overnight bag was placed on the kitchen table. You had stayed overnight at Undyne and Alphys’s little condo, helping the two of them plan for a wedding, with Toriel and Frisk, and even Papyrus. You had planned on staying the night, the rest sort of just...fell asleep.

A smile overtook your face as you remembered helping Undyne tuck the whole crew under every spare blanket in the condo--which, thanks to the fact that both Undyne and Alphys were cold-blooded, meant that there were plenty to spare. The two of you stayed up much too late, still talking about the upcoming wedding anda all the things that had changed since everyone came up to the surface.

Too much to think about now, since you were currently looking for your fire apparition.

“Grillby?” You kicked your shoes off at the door, but you could already feel that the floor was freezing, so you kept your socks on.

You heard a groan and something crashing; your heart began to abuse the inside of your ribs as you started running toward the bedroom. Before you could even reach the door knob, the door was suddenly opening inward. You gasped and your eyes started to dart up before something...caught your eye.

There Grillby was, his hands clenched; one on the door jamb, the other on the door itself--was that smoke coming from under his palms?--and his burning gaze was locked onto you. Oh, and he was completely stark naked, giving you an eyeful of bright orange light that was almost blinding and the hard cock bobbing between his legs.

Oh, his heat came early.

Before you could even move your eyes back up to his face, his arms were around you. Your breath left you and his lips caught yours; heat seared into your body and you could already tell he had been hard at it; you could feel something slick soaking into the front of your shirt near your belly. You grunted; for a moment, the heat gave way to a breath of cold air. You were facing the ceiling with the floor against your back,

Grillby felt like everything was hellfire and need. His body thrummed with an overabundance of magic and pure desire. His hands were already moving up your shirt and pushing it over your breasts. Your bra followed suit and you were moaning beneath him when his mouth found your hard nipple.

“You’re here,” He moaned into your skin and you felt him rut against your covered entrance, dragging his hard cock against your pants, “Fuck, I need you.”

You opened your mouth but his was on yours in a moment; his hips kept moving and you finally wrapped your arms around his back, digging your nails in.

Hot cum covered your pants and stomach as Grillby jerked against you, a whine at the back of his throat. You hissed from the startled moment of white heat before it cooled. You made a small noise of disgust, but it was lost in another kiss from Grillby.

He had been sated, but only for a moment.

“Grillby, just give me a-” You tried to plead, your hands reaching for the button on your pants. Grillby was pulled them down enough to bury his fingers into your folds. You gasped and struggle with your legs, feeling weak-kneed even as you laid on the floor. Somehow, you manage to free one leg. Grillby leaped on this change, hooking his arm under your knee and opening you wider for his touch and gaze.

You shuddered; you had never actually been with Grillby with a heat before. He said because he was something close to an elemental, his cycles were longer but much more drawn out.

“Only if I don’t have a significant other,” He had explained, “When I’m with someone, it only lasts little while.”

“Well, how long is a ‘little while’ to someone who’s immortal?” You raised an eyebrow.

“A week, maybe add a half,” Grillby tilted his head and smiled in a way you found way too kissable.

You cried out. One of Grillby’s fingers had pressed inside and was pressing diligently into the one spot he knew drove you wild. You swallowed and tried to breathe, but you felt like you were suffocating. Your nails dug into his back again and he hissed.

Grillby was already pressing his cock to your entrance and his hips rocked slowly.

“A-already?” You gasped. You were still able to see Grillby’s glow from behind your closed eyelids.

His thumb pressed against your lips and you opened your mouth to catch it with your teeth. Grillby’s hips thrust deeper, filling you. Heat began to follow your veins, energy possessed and you gasped. Your soul pulled out of your chest and you whimpered with Grillby immediately leaned forward and kissed it.

You gasped quietly, your eyes suddenly dazzled. Just behind your soul, you saw a faint glowing white light. It was Grillby’s soul. It had to be. It was a fun fact that human souls were brought out for encounters and only two things triggered these encounters: a Fight, and sex. In all your time with Grillby, you had never seen his soul. Not that he wasn’t willing, you had just been afraid.

Monsters were being of pure magic, which was centered at their soul. You had known this since Toriel had explained it to you. If you damaged Grillby’s soul accidently, that was it. You knew there was some sort of rule about intent, but you couldn’t help your fear.

Now, you were enthralled. The soul looked like yours, but it was upside down and while your soul was colored a glowing aqua, his was pure white. Your breath caught in your throat when you realized your hand was already about to touch it. You hesitated. Grillby whimpered.

“Don’t stop,” His voice was husky and he almost growled the words out.

His soul was cooler than he was, which surprised you. It gave, just like flesh and seemed to press closer to your hand the longer you stroked it's surface. Grillby’s hips bucked and he cried out, your name breaking free from his throat.

Your heart hammered in your chest and your body tightened around him. You didn’t know how long you could keep up with the pace Grillby set; the fire elemental slammed his hips against yours, delicious pleasure washing away the knowledge that you’d be sore long before Grillby was sated.

“Grillby, Grill-AH!” You choked on air when you felt something hot fill you. He had come again and now he was giving you long, slow strokes that left you arching against the floor and begging through his kisses.

“You’re so beautiful,” He speaks into your skin, searing the words like permanent reminders in your flesh, “So soft; I can’t ever get you out of my head. You’re always there, like an angel.”

You aren’t even sure he understands half of what he’s saying, but it's doing a number on you, regardless.His hips buck into your and he’s away again. His body possessed by pleasure and sharing it with you. You whimpered and reached out to pull him into a kiss, searing and pleading.

His fingers reach down between the two of you; his thumb pressed into your cliit while his cock slid between your folds. He circled your clit in time with his thrusts and you were a mess from it. You felt your muscles spasm and your toes curled. Your back arched and you rolled your hips to meet him halfway. 

“Fuck, fuck!” Grillby gasped and bit your shoulder. You hiccuped and came undone.

Your orgasm rocked through you, and the only thing keeping you from screaming was Grillby’s thumb, which pressed into your mouth again. Grillby shot another hot load into you, and you could feel it start to leak out of you with every thrust. You fell back; your body shook and you panted. Your arms landing next to your head, while Grillby pulled back to look down at you.

“A week, huh?” You swallowed and licked your lips.

Grillby smiled, watching you with lidded eyes, “Or a little longer.”

Somehow, the small bubble of excitement in your stomach didn’t surprise you; Grillby was already moving you toward the bed, intent on having you again. You were just glad there was enough of a reprieve for you to catch your breath. Something told you, it would be awhile before you would be able to catch it again.


End file.
